1. Field Of The Invention
This invention relates to apparatus and associated method for determining tension of a rolling mill strip at discrete transverse locations on the strip and providing corrective action where portions of the tension profile depart from predetermined desired levels.
2. Description Of The Prior Art
It has been known in connection with the monitoring of tension in metallic strip in rolling mills to employ an axially rotatable roll which is in contact with the strip and urges the strip out of a planar path of travel. In such systems, it has been known to obtain information regarding the tension in the strip and to make adjustments to the roll position based upon such information. See generally U.S. Pat. Nos. 2,569,264 and 3,961,510.
It has been known in the rolling mill environment to monitor strip tension or flatness by measuring forces across a roll or a segmented group of rolls. See generally U.S. Pat. Nos. 3,475,935; 4,289,005; 4,512,170; and Japan No. 59-1013.
U.S. Pat. Nos. 3,581,536 and 4,332,154 disclose segmented roll, contacting sensor systems.
U.S. Pat. No. 4,116,029 discloses a device which has high inertia rolls and would require prolonged mill shutdown in order to replace the transducers.
U.S. Pat. No. 4,188,809 discloses a segmented roll, noncontacting system wherein the roll surface which is subject to wear is employed as a reference for the sensor. This could interfere with the accuracy of measurement.
See, generally, Proceedings Vol. 1, International Conference on Steel Rolling (Science and Technology of Flat Rolled Products) Sept. 29/Oct. 4, 1980 --Tokyo, Japan, published by the Iron Institute of Japan.
U.S. Pat. No. 3,817,095 discloses a device for detecting and correcting strip defects wherein a strip contacting roll, which may be segmented, engages the strip and a pair of rotatable wheels which are operatively associated with hydraulic cylinders. It provides no disclosure of the handling of hydraulic fluid in a control mode. See also U.S. Pat. Nos. 3,499,306; 3,526,114; and 4,463,586.
In spite of the known prior art practices, there is lacking an effective means for controlling strip tension profile in an economical and rapid manner.